Diamond drill bit



()ci- 5, 9 c. E. CARPENTER ET AL. 2,217,839

DIAMOND DRILL BIT Filed 001:. 20, 1938 mrf ATTORNEYS Patented Oct. 1 5,1940 UNITED STATES DIAMOND DRILL BIT Clarence E. Carpenter and RaymondC. Lynch,

Seattle, Wash., assignors to Diamond Bit Corporation, Seattle, Wash., acorporation of Washington Application October 20, 1938, Serial No.235,978

1 Claim. (01. 255-1) This invention relates to improvements in diamondtools and is specifically directed to the provision of a diamond drillbit particularly adapted for drilling holes which do not require thetaking of core.

It is one of the objects of the present invention to provide a diamonddrill bit which is so constructed that it will completely bore or drilla hole in hard rock and not merely form an annular cut with a centralcore which must be cut away.

More specifically the present invention provides a diamond drill bitinwhich the working face of the bit is concaved, the diamonds set in thisconcave face pointing toward the axis of rotation of the bit. All of thediamonds are offset from the center line of the bit so as to sweep" orhave movement about the axis of rotation of the bit as the bit isrotated, to provide the desired cutting operation. By providing this.concaved n face it will be apparent that the edges of the bit are inadvance and while there are no diamonds at the exact bit center,nevertheless they are in such close proximity to the axis of rotationthat we are assured that all of the rock formation.

2:. from the edgeof the bit to the axis of rotation will be cut andbroken away, thereby avoiding the necessity of taking a core.

Still further objects of the invention will be manifest from thefollowing description and the accompanying drawing, in which drawing:

Fig. 1 is a plan view of the cutting face of our improved'drill bit; and

Fig. 2 is a vertical sectional view of the bit.

Referring to the drawing in detail: The bit 5 comprises a hollow bodyportion 2 of any suitable metal screw threaded either internally orexternally at its inner end as shown at 4 for attachment of the drilltubes or shanks and to permit 'of the admission of wash water for sludgere- 40 moval as will be referred to presently.

As will be seen from Fig. 2, the end wall 6 of the bit is concave andsolid at thecenter, and diamonds 8 are mounted therein.

As will be seen from the drawing, the diamonds 45 point toward the axisof rotation of the bit and inasmuch as there are no diamonds at the axisof rotation, every. stone has a sweep or movement about this axis. As aconsequence of this construction every stone will perform the desired 5cutting and drilling operation, and while there is no diamond at theaxis of rotation, some of the diamonds are in such close proximitythereto that any relatively small unsupported portion of the rock whichmay be left readily breaks away 5 and is ground up by the diamonds inthe drilling operation so that the necessity of taking a core isavoided. It will be appreciated, also, that this construction providesthat the edges of the bit are in advance of the center.

The perimeter or annular rim ID of the bit is 5 flat with diamondsmounted therein. This constructiqn promotes the drilling of a straighthole in that there is no tendency for the drill to veer to one side.

It will be appreciated that by the foregoing con- 1 struction all of thematerial ahead of the bit will be cut up or ground up and that thenecessity of taking a core is completely avoided.

The rock formation as it is ground and cut up in the operation of ourbit. is removed by a flow of wash water. For this purpose we provide thebit with a cutout or waterway I2. This waterway is located close enoughto the center of rotation of the bit to insure a flow of water to thatpoint and still is far enough removed from the center of rotation topermit of diamonds being located between the waterway and this point soas to provide'the cutting area above alluded to immediately adjacent theaxis of rotation of the bit.

The waterway, as will be seen from the drawing, extends in a curvilinearpath from a point M to the outside or perimeter of the bit and then a.short distance in a curve longitudinally along the outside of the wallthereof.

This contour or formation of the waterway i2 insures a flow of water,which may be under pressure, to the center of the concave portion of thebit. The relative size of the waterway serves to protect the diamondsfrom water out. The portion of the. waterway on the outside of the bitis of sufficient size to accommodate the large amount of sludge thrownout by the bit. This waterway, on the other hand, however, is not solarge as to cause a heavy drop in water pres- 0 sure. We find also thatthe waterway being lower at the apex of the concaved face of the bit andhigher as it extends to the bit periphery as well as curved, we get thebenefit of centrifugal force which is created when the bit is inoperation, particularly when the bit is running at the high speeds suchas 600 R. P. M. for which these bits are designed. v

The bit of the present invention may be made and the diamonds settherein by any of the well known methods.

The construction, operation and the manifold advantagesof the drill bitof the present invention readily will be understood from the foregoing.

bit, said waterway extending to the outside of the bit and along theoutside face of the bit, and diamonds set in said ooncaved working faceand extending toward the axis of rotation 01' the hit, all of saiddiamonds being oflset radially from the axis of rotation of the bit,some of said diamonds being disposed intermediate the inner end of thewaterway and the axis of rotation of the bit.

CLARENCE E. CARPENTER. RAYMOND C. LYNCH.

